Method and apparatus for long-term assisting a left ventricle to pump blood

ABSTRACT

A method and apparatus for long-term assisting the left ventricle of a heart to pump blood is disclosed which includes at least one transluminally deliverable pump and a transluminally deliverable support structure which secures the at least one pump within the aorta for long-term use.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/185,974 filed on Jul. 19, 2011, now U.S. Pat. No. 10,413,648, whichis a continuation of U.S. patent application Ser. No. 11/202,795 filedon Aug. 12, 2005, now U.S. Pat. No. 8,012,179, which claims the benefitand priority of U.S. Patent Application Ser. Nos. 60/601,733 filed Aug.13, 2004, and 60/653,015 filed Feb. 15, 2005.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a method and apparatus for long-term assistingthe left: ventricle of a heart to pump blood. A left ventricle assistdevice and associated methods are disclosed.

Description of the Related Art

With the advent of new drugs, percutaneous transluminal coronaryangioplasty, commonly known as “balloon angioplasty” and the use ofstents in combination with balloon angioplasty, effective treatments areavailable for heart disease, as it relates to coronary arteries. Themajor problem currently in treatment of heart disease is treatingindividuals having congestive heart failure or who may require a hearttransplant. In this regard, it is believed that only certain very illpatients may require a heart transplant, whereas many other individualswith heart disease could benefit from a less complicated, costly, andinvasive procedure, provided the individual's heart can be somehowassisted in its function to pump blood through a person's body.

To this end, left ventricle assist devices (“LVAD”) are in current usethat can boost the heart's pumping ability, without replacing thepatient's heart by way of a heart transplant. While presently availableleft ventricle assist devices do provide a benefit to patients withheart disease who require either a heart transplant or assistance inpumping blood throughout the body, it is believed that currentlyavailable devices have certain disadvantages associated with them.Conventional left ventricle assist devices generally require surgeryupon the heart itself, including surgical incisions into the heart,which may weaken the heart, as well as requires a complicated procedureto implant the left ventricle assist device.

Most LVAD implantations require a midline sternotomy of the chest andutilization of cardiopulmonary bypass. Newer devices can be implantedthrough a lateral thoracotomy and can be done without usingcardiopulmonary bypass; however, large loss of blood may occur duringthis procedure. It is also important to note the fact that all currentlong term LVAD devices require operation on the heart itself anddisruption of the myocardium, which can lead to further problems,including arrhythmias, and left and right ventricular dysfunction, whichcan lead to poor outcomes in the patients. The major disadvantage intreating patients with chronic congestive heart failure through asurgical approach is that there is a significant risk of the surgeryitself, including just the use of general anesthesia itself and the useof the heart lung machine. Patients with chronic congestive heartfailure have impaired liver, renal, pulmonary and other organ function,and therefore, are prone to multiple complications following surgery. Asa result, current long-term implantable left ventricular assist deviceshave a one-year mortality rate of greater than 30%.

Currently available left ventricle assist devices may include pumpsplaced within the left ventricle of the heart. Currently availabledevices typically include relatively long conduits, or fluidpassageways, in fluid communication with the heart, and through whichthe person's blood must flow and be pumped therethrough. It is believedthat the long conduits may become sites for thrombosis, or blood clots,which can possibly lead to strokes and other complications. During manyof the procedures to implant such currently available devices, bloodtransfusions are required due to excessive bleeding by the patient.Additionally, the surgery upon the heart may lead to Right HeartFailure, which is the leading cause of early death in present patientsreceiving implanted left ventricle assist devices. Presently availableleft ventricle assist devices, which are connected to the aorta of thepatient, can lead to unbalanced blood flow to certain branch vessels ascompared to others. For example, the blood flow from the aorta tocertain blood vessels that branch off the aorta, such as the coronary orcarotid arteries, may be diminished. Lastly, present LVADs, which areimplanted without chest surgery (percutaneous LVADs), are typically onlyused for a relatively short period of time, generally on the order of7-10 days, whereas it would be desirable for a long-term treatment—onthe order of months or even years—for patients with severe chroniccongestive heart failure who cannot withstand conventional surgery.

Accordingly, prior to the development of the present invention, therehas been no method and apparatus for long-term assisting the leftventricle of the heart to pump blood which: does not require surgeryupon the heart itself; does not require long conduits, or fluidpassageways, to connect the device to the heart; supplies a balanced andnormal blood flow, or physiologic blood supply, to branch vessels, suchas the coronary and carotid arteries; can be implanted without the useof general anesthesia; can be implanted and used for a long period oftime; and can be transluminally delivered and implanted in a cardiaccatheterization lab setting with minimal blood loss and relatively lowrisk of morbidity and mortality. Therefore, the art has sought a methodand apparatus for long term assisting the left ventricles of the heartto pump blood, which: does not require surgery, or incisions upon theheart itself; does not require open chest surgery; does not requirelengthy conduits, or fluid passageways, through which the blood mustflow and be pumped through; is believed to provide a normal and balancedblood flow or physiologic blood supply, to branch vessels such as thecoronary and carotid arteries; can be transluminally delivered andimplanted without the use of general anesthesia; can be implanted andused for a long period of time; and can be implanted in a cardiaccatheterization lab setting by a cardiologist with minimal blood lossand relatively low risk of morbidity and mortality.

SUMMARY OF THE INVENTION

In accordance with the present invention, the foregoing advantages arebelieved to have been achieved through the present long-term leftventricle assist device for assisting a left ventricle of a heart inpumping blood. The present invention may include a transluminallydeliverable pump and a deliverable support structure, which may beimplanted in the catheterization laboratory.

The method and apparatus for assisting the left ventricle of the heartto pump blood of the present invention, when compared to previouslyproposed methods and apparatus, is believed to have the advantages of:not requiring surgery, or incisions, upon the heart itself; notrequiring the use of lengthy conduits, or fluid passageways, throughwhich blood must pass through and be pumped through; supplying a normaland a balanced blood flow, or physiologic blood supply, to branchvessels, such as the coronary and carotid arteries; can be implantedwithout the use of general anesthesia; not requiring a chest surgery;can be implanted and used for a long period of time; and can betransluminally implanted in a cardiac catheterization lab setting withminimal blood loss and relatively low risk of morbidity and mortality.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a front view of a current left ventricle assist device,illustrating its location within a patient's body;

FIG. 2 is a partial cross-sectional view of a heart, to illustrate itsfunctions and anatomy;

FIG. 3 is a partial cross-sectional view of the left ventricle assistdevice of the present invention in a first transluminal deliveryconfiguration, the device being enlarged for clarity;

FIG. 4 is a partial cross-sectional view of the left ventricle assistdevice in accordance with the present invention in a second deployedconfiguration;

FIG. 4A is a partial cross-sectional view of another embodiment of theleft ventricle assist device in accordance with the present invention ina second deployed configuration;

FIG. 5 is perspective view of a power connection for the left ventricleassist device in accordance with the present invention;

FIG. 6 is a perspective view of another embodiment of a power connectionfor the left ventricle assist device in accordance with the presentinvention;

FIG. 7 is a side view of a connection flange in accordance with thepresent invention;

FIG. 8 is a front view of the connection flange of FIG. 7 ;

FIG. 9 is a partial cross-sectional view of an embodiment of the leftventricle assist device in accordance with the present invention,similar to that of FIGS. 3 and 4 , including a one-way valve;

FIG. 10 is a partial cross-sectional view of the left ventricle assistdevice of the present invention being deployed in the ascending aorta;

FIG. 11 is a partial cross-sectional view of another embodiment of theleft ventricle assist device of the present invention in a firsttransluminal delivery configuration, the device being enlarged forclarity; and

FIG. 12 is a partial cross-sectional view of another embodiment of theleft ventricle assist device in accordance with the present invention ina second deployed configuration.

While the invention will be described in connection with the preferredembodiments shown herein, it will be understood that it is not intendedto limit the invention to those embodiments. On the contrary, it isintended to cover all alternatives, modifications, and equivalents, asmay be included within the spirit and the scope of the invention asdefined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 , a currently available left ventricle assist device 70 isshown to include: an inflow conduit, or fluid passageway, 71, disposedbetween the lower portion of the left ventricle 72 of heart 73 and adevice housing 74; and an outflow conduit 75 disposed between the devicehousing 74 and a portion of the ascending aorta 76 of heart 73. Device70 also includes an associated source 77 of suitable power and relatedsensors 78, all operatively associated with device housing 74 in a knownmanner.

As previously discussed, the implantation of left ventricle assistdevice 70 within the body 79 requires surgery incisions upon the heart73, where the inflow conduit 71 is attached to heart 73. As alsopreviously discussed, although left ventricle assist devices presentlyin use, such as device 70 illustrated in FIG. 1 , do provide the bestpresently available level of care for patients awaiting a hearttransplant, by assisting the patient's heart 73 to pump his or her bloodthrough the patient's body, such currently available left ventricleassist devices are believed to have certain previously discusseddisadvantages. These disadvantages relate to: the use of the lengthyconduits, or flow passageways, and the particularly long outflow conduit75; and the requirement of an actual incision and surgery upon the heartmuscle, including blood loss and use of general anesthesia in order toconnect the inflow conduit to the left ventricle 72 of heart 73. In theregard, some devices also include implanting components thereof withinleft ventricle 72 of heart 73. The currently available left ventricleassist devices, such as device 70 of FIG. 1 , although suffering fromthe previously described disadvantages, is also an acceptable device forhelping patients who may not need a heart transplant, or cannotwithstand the rigors of such a surgery, but who may similarly benefitfrom having assistance provided in pumping blood through their body.

With reference to FIGS. 3-4 , a left ventricle assist device 80 inaccordance with the present invention is illustrated in conjunction witha patient's heart 73. Before describing the left ventricle assist device80 of the present invention, a brief description of the functioning ofheart 73 and associated arteries will help in understanding the leftventricle assist device 80 as will be hereinafter described.

In general, the heart 73 consists of two pumps lying side by side. Eachpump has an upper chamber, or atrium, and a lower chamber, or ventricle,as will hereinafter be described. Heart 73 functions to provide aperson's body 79 (FIG. 1 ) with a continuous supply of blood asillustrated by arrows 81 throughout FIGS. 2-6 . In general, the rightside of heart 73 receives “used” blood from the veins (not shown) of aperson's body, and this blood is pumped to the lungs (not shown) of theperson's body to be oxygenated. The oxygen-rich blood from the lungs isthen returned to the left side of the heart, which pumps it through thevarious arteries. Heart 73 requires its own supply of blood to keep itbeating. Oxygen-rich blood is pumped to the chambers, or ventricles, ofthe heart through the coronary arteries, as will be hereinafterdescribed. Once the blood has been used, it is returned to the rightside of heart 73 through a network of veins.

The functioning of these elements of heart 73 may be described inconnection with FIGS. 2 and 5 . Deoxygenated blood flows from veins,such as vein 82 into the right atrium, or right upper chamber, 85 ofheart 73, as illustrated by arrows 81′. Deoxygenated blood 81′ thenflows through the one-way tricuspid valve, or right atrioventricularvalve, 86′ into the right lower chamber, or right ventricle, 86 of heart73. Contraction of the muscle surrounding right ventricle 86 pumps theblood through the semilunar valve, or pulmonary valve 87, and along thepulmonary arteries 88 through the lungs (not shown), where thedeoxygenated blood 81′ receives oxygen. The ascending pulmonary arteryis designated 89, from which pulmonary arteries 88 branch. Oxygenatedblood, as represented by arrows 81″ flows from the lungs into the leftupper chamber, or left atrium, 90 and then passes downwardly throughmitral valve, or left atrioventricular valve, 91 into the left lowerchamber, or left ventricle, 72. Muscle surrounding the left ventricle 72contracts and pumps the blood 81″ through the semilunar valve, or aorticvalve, 92 into the aorta, or ascending aorta, 76, and descending aorta98. The oxygenated blood 81″ is then circulated through the body'sarteries and ultimately returned as deoxygenated blood 81′ to the rightside of heart 73 as previously described. As previously described,oxygen-rich blood 81″ is pumped to the left and right sides of heart 73through the left coronary artery 95 and right coronary artery 96. Aspreviously described, once the oxygen-rich blood 81″ has been used, theblood is returned to the right side of the heart through a network ofveins 97.

With reference to FIGS. 3 and 4 , the left ventricle assist device 80 ofthe present invention includes: a pump 110 which is percutaneously andtransluminally delivered to a portion of the descending aorta 98 (FIGS.2 and 4 ) of a patient 79 via the femoral artery 10 (FIG. 3 ) of apatient 79; and a transluminally deliverable support structure 120 whichsecures, or anchors, pump 110 within the descending aorta 98. Leftventricle assist device 80 is disposed within a portion of thedescending aorta 98, preferably in a central portion of the descendingaorta 98. Pump 110 pumps, or pulls, blood 81″ downward from theascending aorta 76, and thereafter the oxygenated blood 81″ from leftventricle 72 is then circulated through the various arteries of thepatient's body.

Still with reference to FIGS. 3 and 4 , pump 110 is a rotary pump andpreferably is an axial flow pump 111 having first and second ends 112,113, and pump 110 is preferably disposed within a housing 114. At leastone spiral vane, or impeller, 115 is disposed within housing 114.Housing 114 may be approximately 20 French diameter in size, althoughother sizes may be selected. Pump 110 is preferably powered by a motor116, such as an electric motor 116′, which rotates impeller 115.Impeller 115 may be mounted on bearings, or magnetically levitated, forrotation within housing 114. A power wire 117 is associated with motor116, and as will hereinafter described in greater detail, it extendsfrom left ventricle assist device 80 to a point at which it may beassociated with a power source, such a battery (not shown). Housing 114may be provided with a fluid port, e.g., a top cover, or inflow cage,155 which permits the passage of blood 81″ into housing 114, as it isdrawn into, pumped, or pulled into housing 114 by the rotation ofimpeller 115. Housing 114 is preferably made of a suitable metallic orplastic material, such as stainless steel, which is a bio-compatiblematerial. Alternatively, other bio-compatible materials, includingplastic materials, having the requisite strength and bio-compatibilitycharacteristics which permit the desired use in a person's aorta may beutilized. If pump 110 is an axial flow pump 111, impeller 115 wouldrotate about the longitudinal axis 119 of housing 114.

Still with reference to FIGS. 3 and 4 , support structure 120 of leftventricle assist device 80 includes a plurality of support members 121associated with pump 110, which are preferably associated with housing114. Support members 121 may be secured to the outer surface, or outerwall surface, 114′ of housing 114 in any suitable manner, such as bywelding or adhesive bonding. Support structure 120 supports pump 110within the descending aorta 98, preferably in a generally, centrallyspaced relationship from the interior wall surface 98′ of descendingaorta 98. As will be hereinafter described in greater detail, supportstructure 120 anchors pump 110 within descending aorta 98 for long-termuse to assist the pumping of blood 81″ from ascending aorta 76downwardly through descending aorta 98. At least two support members, orstruts, 121 are disposed toward the upper end 112 of pump 110 and towardthe lower end 113 of pump 110. Preferably, at least three supportmembers, or struts 121, are substantially equidistantly disposed aroundeach of the upper and lower ends 112, 113 of pump 110. Preferably, thesupport members 121 have are formed of a suitable bio-compatiblematerial, such as stainless steel. Alternatively, other bio-compatiblematerials, including plastic materials, having the requisite strength,expansion or spring, and bio-compatible characteristics to function inthe manner hereinafter described in a person's aorta 98 may also beutilized. As shown in FIG. 3 , the support structure 120, or pluralityof support members 121 are disposed in a first configuration forpercutaneous transluminal delivery to the desired portion of thedescending aorta 98, as will be hereinafter described. In the firstconfiguration, support members 121 are disposed substantially adjacentthe outer wall surface 114′ of housing 114, and are disposedsubstantially parallel to the longitudinal axis 119 of housing 114. Inthis first configuration, the overall diameter of pump 110, housing 114,and support structure 120 is reduced to permit the percutaneoustransluminal delivery of the left ventricle assist device 80 through thefemoral or iliac artery 10 of the patient to the desired location withinthe descending aorta 98.

The support members, or struts 121, may be disposed in the configurationshown in FIG. 3 as by a sheath 130 or annular bands (not shown), whichmay be subsequently removed, or alternatively, the struts, or supportmembers 121, when initially attached to the outer wall surface 114′ ofhousing 114, have the disposition shown in FIG. 3 .

Upon the left ventricle assist device 80 being positioned within thedesired portion of the descending aorta 98, the support members, orstruts, 121, have a second, expanded configuration wherein the outerends 122 of the support members 121 contact the inner wall surface 98′of descending aorta 98. The second disposition of the support members121 shown in FIG. 4 may be achieved in a variety of ways. For example,the support members 121 may be formed as leaf springs, or springmembers, wherein the support members 121 are biased to spring outwardlyinto the configuration shown in FIG. 4 . If support members 121 are inthe form of leaf springs which bias outwardly toward descending aorta98, they may be initially restrained into the configuration shown inFIG. 3 , by a sheath 130 or band-like member, as previously described,which may be removed when left ventricle assist device 80 has beendelivered to its desired location within the descending aorta 98,whereby the support members, or struts, 121 would move outwardly intothe configuration illustrated in FIG. 4 . Alternatively, support members121 could be formed of a material, such as nitinol, whereby the supportmembers 121 would initially have the configuration shown in FIG. 3 , andupon being heated by the blood flowing within aorta 98 would springoutwardly into the configuration illustrated in FIG. 4 .

Other devices and structures could be utilized for support structure120, provided they permit the percutaneous trans luminal delivery of theleft ventricle assist device 80, and that after such delivery, thesupport structure 120 permits the disposition of the left ventricleassist device within the descending aorta for long-term use, as shown inFIG. 4 . By use of the terms “long term” and “long-term use”, it ismeant to be more than the relatively short period of time thatconventional percutaneous LVADS are used for (e.g. greater than 7-10days, as previously described), and preferably on the order of at leasta month and perhaps even a year or more. For example, a self-expandingstent 200, or stents, as are known in the art could be used forsupportive structure 120, to support pump 110 in a substantially,centrally spaced relationship from the interior wall surface 98′ ofaorta 98, as shown in FIGS. 11 and 12 . The stent, or stents, 200,schematically shown in FIGS. 11 and 12 , could have pump 110 centrallydisposed therein with support members, or struts 121, being attached tothe interior of the stent as shown in FIG. 11 . The stent 200 with thepump, and struts disposed therein, could be compressed and disposedwithin a sheath 130, as hereinafter discussed and transluminallydelivered as seen in FIGS. 11 and 12 , in a manner similar to and asshown as described with reference to FIG. 3 . Upon removal of sheath 130the self-expanding stent 200 with pump 10 and struts 121 would expandoutwardly as seen in FIG. 12 , similar to FIG. 4 , whereby the pump 110would be supported in a generally centrally spaced relationship from theinterior wall surface 98′ of aorta 98.

With reference to FIGS. 3 and 4 , preferably, the outer end 122 of atleast one strut 121, and preferably each of the outer ends of thesupport members, or struts, 121 are provided with an anchor element,such as a small hook 123, or similar structure, which serves to anchoreach of the struts 121 at the desired location within descending aorta98. If desired, a plurality of anchor elements may be used. Preferably,the left ventricle assist device 80 of the present invention isinitially sheathed in a sheath 130 of approximately 22 to 23 French sizein diameter in its undeployed configuration, as show in FIG. 3 . If thestruts 121 are of a spring-type design, the sheath 130 retains thesupport members 121 in the desired configuration illustrated in FIG. 3 .Housing 114 preferably has a diameter of approximately 20 French. Thestrut system, or struts 121, may also be deployed as a separate unitfrom the pump and initially deployed, and thereafter the pump 110 canthen be deployed into the center of the strut system utilizing a lockingmechanism, so that the pump may be removed and replaced at a later dateso as to allow the ability to replace the pump if it should fail.Additionally, two or more pumps 110, 110′ may be placed in parallel inthe descending aorta with one pump being designed in a more cranialposition and the other pump in a more caudal position, so as to allowfor redundancy of the pumps in case one fails and to allow for morepumping capability while utilizing the same French size sheath fordelivery, as shown in FIG. 4A.

It should be apparent to one of ordinary skill in the art that otherpumps 110 could be utilized in lieu of axial flow pump 111, providedpump 110 is bio-compatible and capable of operating in the environmentof the body, specifically the aorta, and able to pump blood 81″. Pump110 may be powered by an implanted power device, or transformer, and mayreceive electric power from either an implanted power source or from asource of power located outside the patient's body 79. It should bereadily apparent to one of ordinary skill that if desired other types ofpower could be utilized to power pump 110, such as hydraulic power orother types of power sources. The implanted power device, not shown,could be a conventional battery or a plutonium, or other nuclearmaterial, power source.

With reference to FIG. 5 , a power connection 135 for left ventricleassist device 80 is shown, with power wire 117 extending from the leftventricle assist device 80 being associated with a tubular shaped graft131. The power wire 117 extends into the interior 132 of graft 131 andpasses outwardly of the graft 131 through the wall surface of the graft131 and includes a portion 118 of power wire 117 extending outwardlyfrom graft 131. As will be hereinafter described in greater detail, thegraft 131 is connected or anastamosed to the patient's femoral artery 10(FIG. 3 ), or other suitable body passageway, and it is desirable thatblood flowing within graft 131 does not leak from graft 131 at thelocation through which power wire 117 passes through graft 131. Graft131 may be formed as a woven Dacron graft, as are known in the art. Toprovide the desired sealing about power wire 117, the individual wires117′ forming the composite power wire 117 may be woven into the interiorsurface of graft 131 and passed outwardly through the wall surface ofthe graft 131 at which point the individual wires 117 are recombinedinto the portion 118 of power wire 117 extending outwardly of graft 131.Graft 131 may have an approximate length of 2-3 cm. The external portion118 of power wire 117 may then be connected to a transcutaneous energytransmission coil (not shown), which may be placed just under the skinin the patient's thigh region. The transcutaneous energy transmissioncoils may then receive electrical energy from another transcutaneousenergy transmission coil, or antenna, worn by the patient in closeproximity or remotely to the implanted transcutaneous energytransmission coil. Thus, power may be supplied to pump 110 via powerwire 117. Alternatively, power wire 117 could pass through Dacron graft131 or the vessel wall itself and a suitable bio-compatible sealantcould be used to provide the requisite seal between power wire 117 andgraft 131.

Alternatively, the power wire 117 could be surrounded by standard feltmaterial, and the power wire 117 is exteriorized through the skin midwaydown the patient's thigh, approximate the vastous medialus or lateralusmuscle. The exiting power wire 117, or portion 118, could then beconnected directly to an external battery and a controller device (notshown). The controller (not shown) could be a standard power deliverydevice, delivering proper wattage to allow for a variable range ofoperation of pump 110, whereby pump 110 could pump blood at a rate offrom approximately 0.5 liters/minute to as high as 5 liters/minute,depending upon the needs of the patient. The battery may be connected tothe controller or incorporated within it, with one primary battery and asecond auxiliary battery being utilized. The controller and batteriescould be worn on the patient's belt or up on a holster-type system, orstrapped to the patient's leg via a Velcro type attachment means, orother suitable attachment structure. The transcutaneous energytransmission coil could also be operated to provide varying amounts ofpower to pump 110 so as to also provide for the variable pumping ofblood at a rate of from approximately 0.5 liters/minute to as high as 5liters/minute.

The controller for either system could vary pump speed either insynchronization with the heart rhythm or paced rhythm, or out ofsynchronization with the heart rhythm or paced rhythm to provide optimalflow to the body. The device controller may also have the ability tosense the native electrocardiogram of the patient or the paced rhythm,and thus vary pump speed based upon it, and it may also communicatedirectly or indirectly with an implanted pacemaker, or defibrillatordevice, to optimize flow in this manner. The device controller may alsobe able to sense when the patient is supine or lying down and decreaseor increase overall pump speed to compensate for decreased need whilesupine. The device controller may also sense other physiologicparameters such as bioimpedence, body motion or cardiac performanceparameters and adjust pump speed to optimize flow of blood to the body.

The method, or procedure to transluminally implant the LVAD 80 of thepresent invention may include some, or all, of the following steps.First, the patient is prepared in a catheterization lab in a standardfashion. Under conscious sedation, local anesthesia is applied to thefemoral area, similar to the manner in which a standard heartcatheterization is performed. A small 3 cm incision is made in thevertical plane overlying the femoral artery 10, just below the inguinalligament. The femoral artery is exposed, and may then be entered by theSeldinger technique over a guide-wire and is successively dilated toallow entry of a sheath 140, having a preferred diameter of 23 French(FIG. 3 ). The sheath 140 is then passed over a guide-wire and thenplaced into position in the descending aorta 98, with the tip 141 (FIG.3 ) in the mid thoracic aorta, approximately 4 cm below the take off ofthe left subclavian artery. The sheath 140 is then de-aired. Sheath 140contains at its external end, outside the patient's body, a one-wayvalve and a side arm for de-airing. The LVAD 80 is then passed throughthe one-way valve into the sheath 140 to the tip 141 at the mid thoracicarea. The passage of the LVAD 80 through the sheath 140 is made possiblewith an obturator (not shown). As the obturator is held in place, thesheath 130 is then withdrawn, which in the case of a spring type supportstructure 120, the support members, or struts 121 then spring open andanchor the pump 110 in the descending aorta 98, or alternatively, ifsupport structure 120 is a self-expanding stent 200, stent 200 springsopen and anchors the pump 110 in the aorta 98. The obturator is thenremoved, and the sheath 140 is then pulled back with the power wire 117still passing through, or disposed within, the sheath 140.

The graft 131 (FIG. 5 ) that contains the transarterial wire system, orpower connection 135, is then passed through the one-way valve into thesheath 140, and the sheath 140 is successively withdrawn until thesheath exits the femoral or iliac artery. Just prior to it exiting thefemoral, or iliac, artery, a clamp is placed proximal to the entry siteto prevent excessive bleeding. Thereafter, a small section approximately1.5 cm of the femoral artery is excised, and the graft 131 isanastamosed in an end-to-end fashion in an interposition technique tothe femoral or iliac artery. It is then de-aired. This leaves the transarterial wire, or portion 118 (FIG. 5 ) of wire 117 external to theartery 10, which is then tunneled to a drive line exit site or tunneledunder the skin to a transcutaneous energy transmission coil, which isplaced under the skin. The skin is then closed with suture.

Alternatively, with reference to FIGS. 6-9 , after the sheath 140 isremoved, a clamp is applied to prevent excessive bleeding. At the siteof entry of the power wire 117 into the artery 10, a tubular graft, or asmall flange member 160 is placed via a small delivery tool, which ispassed over the power wire 117. The graft, or flange, 160 is put intoposition and the small delivery tool is removed and any excessivebleeding is observed. The flange member 160 may be made of either Dacrongraft material or an inert polyurethane compound, or other biocompatiblematerial, and flange 160 may also be a thrombin plug with a central hole161 to allow passage of the wire 117. The flange member 160 ispreferably two small, circular shaped members joined by a centralportion 162, which has a central hole 161 through which the wire passes.The flange 160 is preferably 25 French in diameter, whereby it is largeenough to occlude the hole in the artery 10, which was made by the largesheath 140. This flange system allows for externalization of the powerwire 117 from the artery 10 without excessive bleeding while preventingformation of an arterial fistula. The power wire is now external to theartery 10 and can be attached to an internal implanted transcutaneousenergy transmission coil or exteriorized through a drive line aspreviously described.

After access to the artery 10 is gained, anti-coagulation with a shortterm intravenous anti-coagulant is provided during the procedure, andimmediately thereafter, until long-term oral anti-coagulation can beinstituted, if needed.

With reference to FIG. 9 , a figure similar to FIG. 4 , the leftventricle assist device 80 is provided with a one-way valve 170, and isshown disposed in the descending aorta 98. The same reference numeralsare used for the same components shown and described in connection withFIGS. 3 and 4 . One-way valve 170 may be provided to prevent backflow ofblood 81″ from flowing upwardly back into descending aorta 98. One-wayvalve 170 may be provided in any suitable manner, such as by supportingone-way valve 170 by a strut system 171 associated with housing 114.Strut system 171 may include a plurality of strut members 172 which maybe deployed in a similar manner to strut members 121 of strut system 120to bring the circumferential end, or lip, 172 of one-way valve 170 intoa sealing relationship with the interior surface 98′ of descending aorta98. The other, smaller diameter circumferential end, or lip, 174 ofone-way valve 170 is shown in FIG. 9 disposed in its sealed relationshipwith respect to housing 114, whereby backflow of blood 81″ upwardly intodescending aorta 98 is prevented. As blood 81″ is pumped to flowdownwardly into descending aorta 98, one-way valve 170 may open as shownby dotted lines 170′, whereby one-way valve 170 opens as shown in thedirection of arrows 175, whereby the circumferential lip 174 of one-wayvalve 170 moves outwardly from housing 114 to permit blood 81″ to flownot only through pump 110, but from outside housing 114 and intodescending aorta 98.

One-way valve 170 may be made of any suitable bio-compatible, orbiomaterial, including plastic materials, having the requisite strengthand bio-compatibility characteristics which permit the desired use in aperson's aorta and permits the function of one-way valve 170. Rigidbiomaterials, or flexible biomaterials may be utilized for theconstruction of one-way valve 170.

With reference to FIG. 10 , the left ventricle assist device 80 of thepresent invention, having the same general construction as illustratedin connection with FIGS. 3 and 4 is shown disposed, not in thedescending aorta 98, but rather in the ascending aorta 76, withoxygenated blood 81″ being pumped by pump 110 from the left ventricle 72and outwardly into the aortic root, or ascending aorta, 76. In thisembodiment of the left ventricle assist device 80, the housing 114′ islengthened to include an inflow cannula 180, which may be provided witha plurality of openings, or ports, 181 formed in the side walls ofcannula 180. Similar ports 181 may also be provided in the upper end ofhousing 114′, which ports 181 assist in the passage of blood 81″ throughhousing 114′. As shown in FIG. 10 , housing 114′ is anchored withinascending aorta 76 by a plurality of strut members 121, and housing 114′is disposed within aortic valve 92. When the left ventricle assistdevice 80, shown in FIG. 10 , is deployed within the ascending aorta 76,the aortic valve 92 functions as the one-way valve which may beprovided, as discussed in connection with the embodiment of LVAD 80 ofFIG. 9 . It is believed that by disposing the left ventricle assistdevice 80 within the ascending aorta 76, direct unloading of the leftventricle 72 will be provided, so that more efficient afterloadreduction may be accomplished. It is also believed that deployment ofthe left ventricle assist device in the ascending aorta 76 will alsopermit better perfusion of the cerebral circulation. In the embodimentof left ventricle assist device 80 of FIG. 10 , power wire 117′ may beassociated with the upper, or first end, 112 of pump 110.

Alternatively, rather than transluminally implanting the LVAD 80 of thepresent invention through the femoral artery, as previously described,LVAD 80 may be transluminally implanted and delivered through the leftor right subclavian artery, and the power source or battery andcontroller may be placed in the pectoral area of the patient. This typeof implant technique would be similar to the implantation of a cardiacpacemaker or defibrillator, with the exception that access would beobtained through the subclavian artery, rather than the subclavian vein.The power source, and/or its controller, may be incorporated in a devicesuch as a cardiac pacemaker or defibrillator, if used in this manner.

Alternatively, if desired, the pump 110 and support structure 120,including support members 121, could be designed whereby pump 110 andsupport structure 120 could be removed with a catheter based removaldevice (not shown) which could collapse support members 121 anddisengage them from their anchored configuration to permit the removalof them and pump 110, if desired, such as to replace or repair pump 110.Such a catheter based removal device could be similar to those presentlyused with inferior vena cava filters.

The present invention has been described and illustrated with respect toa specific embodiment. It will be understood to those skilled in the artthat changes and modifications may be made without departing from thespirit and scope of the invention as set forth in the appended claims.

What is claimed is:
 1. A blood flow assist system comprising: a pumphousing, wherein the pump housing has an upper end and a lower end; apump disposed within the housing, wherein the pump provides axial bloodflow; and a support structure configured to secure the pump in a desiredlocation in a circulatory system of a patient, wherein the supportstructure comprises: a plurality of support members, wherein the supportmembers are a plurality of struts, at least two struts are disposed atthe upper end of the pump housing and at least two struts are disposedat the lower end of the pump housing, each strut of the at least twostruts comprising an anchor element disposed on a distal end of thestrut, the struts are configurable between a collapsed positiondisengaged from a vessel wall or an expanded configuration where anouter end of the struts contact the vessel wall, wherein the outer endof the struts are at a first tip of a first terminal end of the struts,an inner end of the struts are secured to the pump housing, and theinner end of the struts are at second tip of the struts at a secondterminal end of the strut opposite the first terminal end, and whereinthe blood flow assist system allows native blood flow between anentirety of the pump housing and the vessel wall at all times in theexpanded configuration.
 2. The system of claim 1, wherein the supportmembers are formed as a leaf-spring.
 3. The system of claim 1, whereinthe support members have a first configuration where an overall diameterof the pump, the pump housing, and the support structure is reduced topermit transluminal delivery.
 4. The system of claim 1, wherein thesupport structure is centrally disposed relative to the vessel wall. 5.The system of claim 1, wherein the pump is a first pump, and the systemfurther comprises a second pump, wherein the second pump is placed inparallel with the first pump.
 6. The system of claim 1 furthercomprising a controller, wherein the controller senses a paced rhythm ofa patient, and varies pump speed based on the paced rhythm.
 7. Thesystem of claim 1, wherein the system receives electrical energy from atranscutaneous energy coil or a power wire connected to a power sourceexternal to a patient's body.
 8. A method for providing blood flowassistance to a circulatory system, the method comprising the steps of:preparing a patient for a heart catheterization; making a small incisionnear a blood vessel in a patient's body and performing a Seldingertechnique; passing a sheath over a guidewire, wherein the sheathrestrains a blood flow assist system of claim 1 in the collapsedconfiguration; and delivering a tip of the sheath to a desired positionand deploying the blood flow assist system to the expandedconfiguration.
 9. The method of claim 8, wherein the struts are membersthat are thin, elongated, and narrow in width.
 10. The method of claim8, wherein the delivering and deploying step further comprises de-airingthe sheath and withdrawing the sheath to anchor the system in thedesired position.
 11. The method of claim 8, wherein the system isimplanted for greater than ten days.
 12. The method of claim 8 furthercomprising the steps of sensing a paced rhythm of a patient, and varyingpump speed based on the paced rhythm.